This program-project proposes clinical and experimental laboratory research in the general field of the neurologic abnormalities of the developing nervous system. The work will be a constituent portion of the Mental Retardation and Human Development research program of the institution. We propose to concentrate our attention on clinical and experimental problems in the following areas: 1) Cerebral fluid and solute physiology, and active transport in the CNS; 2) Clinical and experimental electroneurophysiology; 3) neurochemistry (lipid, enzymology and catecholamine); and 4) neuropathology (including ultrastructure).